In any case, all allergies lead to inflammatory responses. Common symptoms include itching, increased mucus production, and raw or swollen tissues of the upper airways. Allergic reactions are, by their very nature, anti-sleep:

Coughing and throat clearing to relieve post-nasal drip, and sneezing to clear passages, is disruptive to your sleep as well as the sleep of your bed partner (see also "second-hand sleep problems")

Stuffy noses lead to frequent tossing and turning to use gravity to help clear airways

Basically, allergies lead to sleep fragmentation. One bad night is not a problem, but most people with allergies don’t have one bad night, but several. And that’s when sleep deprivation kicks in. Unfortunately, one of the problems associated with sleep deprivation is immune system impairment.

Since allergic reactions are an immune system process, a less-healthy immune system will only be further aggravated by lost sleep. It’s truly a vicious cycle, but at least for those who are only allergic to seasonal substances, it’s somewhat temporary. For those who suffer year-round, this is an ongoing dilemma.

What about upper airway resistance?

A closer look at allergy symptoms (seasonal or year round) reveals that allergic responses can lead to a specific kind of sleep breathing event. Respiratory effort related arousals (RERAs) are pauses in breathing that resemble apneas. RERAs tend to be composed of hypopneas, rather than apneas, however.

A person who has a lot of RERAs (or, generally speaking, upper airway resistance) over the course of a night can end up with a serious condition, not unlike obstructive sleep apnea, known as Upper Airway Resistance Syndrome (UARS).

Snoring is also considered a problem of upper airway resistance. When allergies and snoring occur together during allergy season, it practically guarantees you will suffer from UARS.

How to avoid sleep problems due to allergies

If you’ve never been diagnosed with allergies, talk to your doctor. They don’t always happen in childhood and may not occur until you are much older.

The first solution is the most obvious one: treat your allergies aggressively.

If you also snore, talk to a physician about solutions such as an oral appliance or snore guard to treat that problem, as well.

Comfort measures to get you through the night include saltwater irrigation of the nasal passages, drinking more water, elevating the head of your bed by 3 inches, and careful application of over-the-counter medications, which you should use as directed.

Also, it’s sometimes better to anticipate allergy season by using medications in the late winter before pollen counts run high. Pay attention to pollen counts (either in your local newspaper or from online weather apps) and adjust your treatments and activities accordingly. That might include keeping windows and doors closed during peak pollen counts or during the highest levels, which typically occur in the morning.

If your problems are serious, immunotherapy in the form of injections may be successful for certain kinds of allergies.

Finally, practice good sleep hygiene by using HEPA filters in your home, showering before bed, washing your sheets and use pillow protectors to curb dust mite activity, drying your laundry indoors rather than outside, and keeping on top of vacuuming and dusting.

Using CPAP during allergy season

It may seem counterintuitive, but allergy season is a great reason to use your CPAP therapy. Why?

CPAP machines have built-in filters to help keep the air you breathe at night particulate free. Make sure you swap out the disposables and wash any reusable filters regularly to protect this benefit.

Also, the moisture coming from the humidifier is an added bonus. Keep your water chamber free of mineral salts by washing it with mild soap and water at least once a week. Also, conscientious maintenance of your entire CPAP system is generally going to keep most allergens out of your system as you sleep.

Some CPAP machines have ramp features which allow you some control over your pressures; when you’re congested, use of this feature may help to improve your therapy experience. (Tip: Always start off the night with clear nasal passages by using saline sprays, menthol inhalers, neti pot irrigation, or nasal steroid prescriptions.)